Highly Selective Reduction of α, β ‐Unsaturated Aldehydes and Ketones under Ambient Conditions using Tetraalkylphosphonium‐based Ionic Liquids

An efficient and green protocol for highly selective reduction of α,β ‐unsaturated aldehydes and ketones at room temperature is described in a range of ionic liquids, in the absence of noble metal catalysts, by using NaBH 4 as reducing agent. Most notably, using [P 6,6,6,14 ][N(CN) 2 ] ionic liquid, in absence of organic solvent, within 10 min, 97% conversion of cinnamaldehyde was achieved with 100% selectivity towards cinnamyl alcohol. The ionic liquid was easily recycled without any noticeable decline in activity. The reduction protocol was further extended to a variety of α,β ‐unsaturated aldehydes and ketones.